Some of Russell Crowe’s (pictured, honest!) rescuers had no idea that the bald and bearded kayaker they saved off Long Island on Saturday was the film star until they got back to port.

The 48-year-old “Master and Commander” actor looks more like a geezer as he prepares for his role as Noah in a new film he’s shooting in Oyster Bay.

“When we tied up in Huntington, one of the guys that was on the back of the boat told me it was Russell Crowe — I didn’t believe him,” Coast Guard Petty Officer Robert Swieciki, 24, told The Post outside his City Island home yesterday.

“I thought it was pretty cool, you know. I love the movie ‘Gladiator,’ ” another Crowe flick, Swieciki said.

“He probably isn’t happy that everyone knows he got stranded, especially since he was in ‘Master And Commander.’ ”

Crowe and a pal were lost for 4 1/2 hours while kayaking in Lond Island Sound.